Metrics – often referred to as “Key Performance Indicators” or simply “KPIs” – are a necessity, regardless of your field. If nothing else, it’s nigh impossible to say anything meaningful about performance without them, and improving the performance is turned from something quite achievable. to a Sisyphean task.
CSI – that’s Continual Service Improvement, by the way, not Crime Scene Investigation – is, to my mind, the single most important stage in the ITIL service life cycle. It evaluates what has gone before, identifies areas for improvement, and aids in the implementation of improving. In an ideal situation, CSI informs all the other stages, and is the main driver for the service life cycle.